| Author/Editor | Horvat, Milena; Bloom, Nicolas S; Liang, Lian | |
| Title | Comparison of distillation with other current isolation methods for the determination of menthyl mercury compounds in low level environmental samples. Part 1. Sediments | |
| Type | članek | |
| Source | Anal Chim Acta | |
| Vol. and No. | Letnik 281 | |
| Publication year | 1993 | |
| Volume | str. 135-52 | |
| Language | eng | |
| Abstract | In the present study isolation of methyl mercury compounds (MeHg) from sediments by distillation, followed by aqueous phase ethylation, precollection on a Carbotrap, isothermal gas chromatography and cold vapour atomic fluorescence (CVAF) detection, was investigated. Results obtained by distillation were compared with those obtained by alkaline digestion and HCI leaching methods. A good agreement of the results for MeHg in sediments of various origins and wide concentration range (0.04-60.0 ng g-1, dry weight) obtained by distillation and KOH-methanol digestion was found. The main advantage of the distillation method over alkaline digestion is avoidance of matrix effects during the ethylation process. Distillation gives consistent and high recoveries (95 +- 4%) and therefore provides more accurate results especially, at low MeHg concentrations. Detection limits as low as 0.001 ng MeHg g-1 as Hg for 100 mg sample weight were obtained. The HCI leaching method was found to be ineffective in releasing MeHg from sediment quantitatively. Even 8 HCl could not release MeHg quantitatively; on the contrary, if the concentration of HCI was more than 4 M, decomposition of released MeHg occurred. Addition of Cu(II) ions increased the release of MeHg into solution, but not quantitatively. The difference in the results obtained by distillation and HCl leaching was in positive correlation with concentration of MeHg (r2=0.92) and the concentration of total organic carbon (TOC) (r2=0.88). This suggests that the fraction of MeHg released from the sediment by HCl might be of certain interest in studies of the biogeochemical cycle o. Hg. (Abstract truncated at 2000 characters.) | |
| Descriptors | METHYLMERCURY COMPOUNDS ENVIRONMENTAL POLLUTANTS CHROMATOGRAPHY, GAS SPECTROMETRY, FLUORESCENCE MERCURY |